Methods and Configurations for Improving the Performance of Sensors under a Display

ABSTRACT

An electronic device may include a display and a sensor under the display. The display may include an array of subpixels for displaying an image to a user of the electronic device. At least a portion of the array of subpixels may be selectively removed in a pixel removal region to improve optical transmittance to the sensor through the display. The pixel removal region may include a plurality of pixel free regions that are devoid of thin-film transistor structures, that are devoid of power supply lines, that have continuous open areas due to rerouted row/column lines, that are partially devoid of touch circuitry, that optionally include dummy contacts, and/or have selectively patterned display layers.

This application claims priority to U.S. patent application Ser. No.16/825,978, filed on Mar. 20, 2020, and U.S. provisional patentapplication No. 62/837,628, filed Apr. 23, 2019, which are herebyincorporated by reference herein in their entireties.

BACKGROUND

This relates generally to electronic devices, and, more particularly, toelectronic devices with displays.

Electronic devices often include displays. For example, an electronicdevice may have an organic light-emitting diode (OLED) display based onorganic light-emitting diode pixels. In this type of display, each pixelincludes a light-emitting diode and thin-film transistors forcontrolling application of a signal to the light-emitting diode toproduce light. The light-emitting diodes may include OLED layerspositioned between an anode and a cathode.

There is a trend towards borderless electronic devices with a full-facedisplay. These devices, however, may still need to include sensors suchas cameras, ambient light sensors, and proximity sensors to provideother device capabilities. Since the display now covers the entire frontface of the electronic device, the sensors will have to be placed underthe display stack. In practice, however, the amount of lighttransmission through the display stack is very low (i.e., thetransmission might be less than 20% in the visible spectrum), whichseverely limits the sensing performance under the display.

It is within this context that the embodiments herein arise.

SUMMARY

An electronic device may include a display and an optical sensor formedunderneath the display. A pixel removal region on the display may atleast partially overlap with the sensor. The pixel removal region mayinclude a plurality of non-pixel regions each of which is devoid ofthin-film transistors. The plurality of non-pixel regions is configuredto increase the transmittance of light through the display to thesensor. In one suitable arrangement, half of all display subpixels inthe pixel removal region may be removed to increase the transmittance oflight through the display to the sensor. In general, 10-90% of alldisplay subpixels in the pixel removal region may be removed to increasethe transmittance of light through the display to the sensor.

In accordance with an embodiment, a subset of all display subpixels inthe pixel removal region may be removed by iteratively eliminating thenearest neighboring subpixels of the same color. The display may includemore than one pixel removal region, which are of the same or differentsize/shape. The pixel removal region may cover an entire edge of thedisplay. The pixel removal region may cover a corner of the display. Thepixel removal region may cover a notch area in the display. The pixelremoval region may also cover the entire display area. The pixel removalregion may optionally cover any portion of the display.

The plurality of non-pixel regions may also be devoid of vertical powersupply routing traces. If desired, at least some horizontal and verticalcontrol lines in the plurality of non-pixel regions are rerouted toprovide continuous open areas that reduce the amount of diffraction forlight traveling through the display to the sensor. Each of the pluralityof non-pixel regions may also be devoid of dummy contacts or mayalternatively include dummy contacts to help provide emission currentuniformity in the pixel removal region.

The electronic device may further include a conductive touch sensor meshformed over the display. In one suitable arrangement, the conductivetouch sensor mesh is not removed from the pixel removal region. Inanother suitable arrangement, the conductive touch sensor mesh iscompletely removed from the pixel removal region. In yet anothersuitable arrangement, the conductive touch sensor mesh is only partiallyremoved from the pixel removal region. The display may further include ablanket layer that is selectively patterned in the pixel removal regionto increase the transmittance of light through the display to thesensor. The blanket layer may be a display layer selected from the groupconsisting of: a substrate protection layer, a gate dielectric layer, aninorganic passivation layer, and an organic pixel definition layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic devicehaving a display and one or more sensors in accordance with anembodiment.

FIG. 2A is a schematic diagram of an illustrative display withlight-emitting elements in accordance with an embodiment.

FIG. 2B is a circuit diagram of an illustrative display pixel inaccordance with an embodiment.

FIG. 3 is a cross-sectional side view of an illustrative display stackthat at least partially covers a sensor in accordance with anembodiment.

FIGS. 4A-4D are top views showing various pixel removal schemes forimproving optical transmission in accordance with some embodiments.

FIG. 5A is a top layout view showing how red subpixels can besystematically removed in accordance with an embodiment.

FIG. 5B is a top layout view showing how additional red subpixels can befurther systematically removed from the arrangement of FIG. 5A inaccordance with an embodiment.

FIGS. 6A and 6B are diagrams showing an illustrative pixel removalscheme that follows the process illustrated in FIG. 5A in accordancewith an embodiment.

FIG. 6C is a diagram illustrating non-uniform subpixel omission inaccordance with an embodiment.

FIG. 6D is a diagram showing another illustrative pixel removal schemein accordance with an embodiment.

FIG. 6E is a diagram showing a vertical pixel removal scheme inaccordance with an embodiment.

FIG. 6F is a diagram of a pixel arrangement after two pixel removaliterations in accordance with an embodiment.

FIG. 6G is a diagram of a pixel arrangement where more green subpixelshave been removed in accordance with an embodiment.

FIG. 6H is a diagram of a non-pentile pixel arrangement after pixelremoval in accordance with an embodiment.

FIGS. 7A-7F are front views of an electronic device display showing howthe display may have one or more localized regions in which the pixelsare selectively removed using the scheme of FIGS. 4-6 in accordance withsome embodiments.

FIG. 7G is a cross-sectional side view of an electronic device displayshowing how the display may have one or more localized regions in whichthe pixels are selectively removed at a curved edge in accordance withan embodiment.

FIG. 8A is a top layout view showing how subpixel transistors may beselectively removed to increase transmittance in accordance with anembodiment.

FIG. 8B is a top layout view showing how power lines over the removedtransistors may also be omitted to further increase transmittance inaccordance with an embodiment.

FIG. 8C is a top layout view showing how the horizontal and verticalrouting lines may be rerouted to provide a larger continuous opening toreduce optical diffraction in accordance with an embodiment.

FIG. 8D is a top layout view showing how subpixel structures arerelocated along a single row in accordance with an embodiment.

FIG. 8E is a top layout view showing how the size of subpixel structuresmay be enlarged in accordance with an embodiment.

FIG. 8F is a top layout view showing how an opaque mask may be used todefine an aperture opening in accordance with an embodiment.

FIG. 9A is a top layout view showing illustrative touch conductive meshcircuitry formed over the pixel removal region in accordance with anembodiment.

FIG. 9B is a top layout view showing how the touch conductive meshcircuitry may be partially removed over the pixel removal region inaccordance with an embodiment.

FIG. 10A is a top layout view showing how the region where the subpixeltransistors have been removed lacks dummy contacts in accordance with anembodiment.

FIG. 10B is a top layout view showing how the region where the subpixeltransistors have been removed includes dummy contacts in accordance withan embodiment.

FIG. 10C is a plot of emission current versus gate-to-source voltageshowing how the presence of dummy contacts can help improve the emissioncurrent profile in accordance with an embodiment.

FIG. 11 is a cross-sectional side view of an illustrative display stackshowing how at least some of the blanket layers within the display stackcan be selectively patterned to improve optical transmittance inaccordance with an embodiment.

DETAILED DESCRIPTION

An illustrative electronic device of the type that may be provided witha display is shown in FIG. 1. Electronic device 10 may be a computingdevice such as a laptop computer, a computer monitor containing anembedded computer, a tablet computer, a cellular telephone, a mediaplayer, or other handheld or portable electronic device, a smallerdevice such as a wrist-watch device, a pendant device, a headphone orearpiece device, a device embedded in eyeglasses or other equipment wornon a user's head, or other wearable or miniature device, a display, acomputer display that contains an embedded computer, a computer displaythat does not contain an embedded computer, a gaming device, anavigation device, an embedded system such as a system in whichelectronic equipment with a display is mounted in a kiosk or automobile,or other electronic equipment. Electronic device 10 may have the shapeof a pair of eyeglasses (e.g., supporting frames), may form a housinghaving a helmet shape, or may have other configurations to help inmounting and securing the components of one or more displays on the heador near the eye of a user.

As shown in FIG. 1, electronic device 10 may include control circuitry16 for supporting the operation of device 10. Control circuitry 16 mayinclude storage such as hard disk drive storage, nonvolatile memory(e.g., flash memory or other electrically-programmable-read-only memoryconfigured to form a solid-state drive), volatile memory (e.g., staticor dynamic random-access memory), etc. Processing circuitry in controlcircuitry 16 may be used to control the operation of device 10. Theprocessing circuitry may be based on one or more microprocessors,microcontrollers, digital signal processors, baseband processors, powermanagement units, audio chips, application-specific integrated circuits,etc.

Input-output circuitry in device 10 such as input-output devices 12 maybe used to allow data to be supplied to device 10 and to allow data tobe provided from device 10 to external devices. Input-output devices 12may include buttons, joysticks, scrolling wheels, touch pads, key pads,keyboards, microphones, speakers, tone generators, vibrators, cameras,sensors, light-emitting diodes and other status indicators, data ports,etc. A user can control the operation of device 10 by supplying commandsthrough input resources of input-output devices 12 and may receivestatus information and other output from device 10 using the outputresources of input-output devices 12.

Input-output devices 12 may include one or more displays such as display14. Display 14 may be a touch screen display that includes a touchsensor for gathering touch input from a user or display 14 may beinsensitive to touch. A touch sensor for display 14 may be based on anarray of capacitive touch sensor electrodes, acoustic touch sensorstructures, resistive touch components, force-based touch sensorstructures, a light-based touch sensor, or other suitable touch sensorarrangements. A touch sensor for display 14 may be formed fromelectrodes formed on a common display substrate with the display pixelsof display 14 or may be formed from a separate touch sensor panel thatoverlaps the pixels of display 14. If desired, display 14 may beinsensitive to touch (i.e., the touch sensor may be omitted). Display 14in electronic device 10 may be a head-up display that can be viewedwithout requiring users to look away from a typical viewpoint or may bea head-mounted display that is incorporated into a device that is wornon a user's head. If desired, display 14 may also be a holographicdisplay used to display holograms.

Control circuitry 16 may be used to run software on device 10 such asoperating system code and applications. During operation of device 10,the software running on control circuitry 16 may display images ondisplay 14.

Input-output devices 12 may also include one or more sensors 13 such asforce sensors (e.g., strain gauges, capacitive force sensors, resistiveforce sensors, etc.), audio sensors such as microphones, touch and/orproximity sensors such as capacitive sensors (e.g., a two-dimensionalcapacitive touch sensor associated with a display and/or a touch sensorthat forms a button, trackpad, or other input device not associated witha display), and other sensors. In accordance with some embodiments,sensors 13 may include optical sensors such as optical sensors that emitand detect light (e.g., optical proximity sensors such astransreflective optical proximity structures), ultrasonic sensors,and/or other touch and/or proximity sensors, monochromatic and colorambient light sensors, image sensors, fingerprint sensors, temperaturesensors, proximity sensors and other sensors for measuringthree-dimensional non-contact gestures (“air gestures”), pressuresensors, sensors for detecting position, orientation, and/or motion(e.g., accelerometers, magnetic sensors such as compass sensors,gyroscopes, and/or inertial measurement units that contain some or allof these sensors), health sensors, radio-frequency sensors, depthsensors (e.g., structured light sensors and/or depth sensors based onstereo imaging devices), optical sensors such as self-mixing sensors andlight detection and ranging (lidar) sensors that gather time-of-flightmeasurements, humidity sensors, moisture sensors, gaze tracking sensors,and/or other sensors. In some arrangements, device 10 may use sensors 13and/or other input-output devices to gather user input (e.g., buttonsmay be used to gather button press input, touch sensors overlappingdisplays can be used for gathering user touch screen input, touch padsmay be used in gathering touch input, microphones may be used forgathering audio input, accelerometers may be used in monitoring when afinger contacts an input surface and may therefore be used to gatherfinger press input, etc.).

Display 14 may be an organic light-emitting diode display or may be adisplay based on other types of display technology. Deviceconfigurations in which display 14 is an organic light-emitting diodedisplay are sometimes described herein as an example. This is, however,merely illustrative. Any suitable type of display may be used, ifdesired. In general, display 14 may have a rectangular shape (i.e.,display 14 may have a rectangular footprint and a rectangular peripheraledge that runs around the rectangular footprint) or may have othersuitable shapes. Display 14 may be planar or may have a curved profile.

A top view of a portion of display 14 is shown in FIG. 2A. As shown inFIG. 2A, display 14 may have an array of pixels 22 formed on asubstrate. Pixels 22 may receive data signals over signal paths such asdata lines D and may receive one or more control signals over controlsignal paths such as horizontal control lines G (sometimes referred toas gate lines, scan lines, emission control lines, etc.). There may beany suitable number of rows and columns of pixels 22 in display 14(e.g., tens or more, hundreds or more, or thousands or more). Each pixel22 may include a light-emitting diode 26 that emits light 24 under thecontrol of a pixel control circuit formed from thin-film transistorcircuitry such as thin-film transistors 28 and thin-film capacitors.Thin-film transistors 28 may be polysilicon thin-film transistors,semiconducting-oxide thin-film transistors such as indium zinc galliumoxide (IGZO) transistors, or thin-film transistors formed from othersemiconductors. Pixels 22 may contain light-emitting diodes of differentcolors (e.g., red, green, and blue) to provide display 14 with theability to display color images or may be monochromatic pixels.

Display driver circuitry may be used to control the operation of pixels22. The display driver circuitry may be formed from integrated circuits,thin-film transistor circuits, or other suitable circuitry. Displaydriver circuitry 30 of FIG. 2A may contain communications circuitry forcommunicating with system control circuitry such as control circuitry 16of FIG. 1 over path 32. Path 32 may be formed from traces on a flexibleprinted circuit or other cable. During operation, the control circuitry(e.g., control circuitry 16 of FIG. 1) may supply display drivercircuitry 30 with information on images to be displayed on display 14.

To display the images on display pixels 22, display driver circuitry 30may supply image data to data lines D while issuing clock signals andother control signals to supporting display driver circuitry such asgate driver circuitry 34 over path 38. If desired, display drivercircuitry 30 may also supply clock signals and other control signals togate driver circuitry 34 on an opposing edge of display 14.

Gate driver circuitry 34 (sometimes referred to as row controlcircuitry) may be implemented as part of an integrated circuit and/ormay be implemented using thin-film transistor circuitry. Horizontalcontrol lines G in display 14 may carry gate line signals such as scanline signals, emission enable control signals, and other horizontalcontrol signals for controlling the display pixels 22 of each row. Theremay be any suitable number of horizontal control signals per row ofpixels 22 (e.g., one or more row control signals, two or more rowcontrol signals, three or more row control signals, four or more rowcontrol signals, etc.).

The region on display 14 where the display pixels 22 are formed maysometimes be referred to herein as the active area. Electronic device 10has an external housing with a peripheral edge. The region surroundingthe active and within the peripheral edge of device 10 is the borderregion. Images can only be displayed to a user of the device in theactive region. It is generally desirable to minimize the border regionof device 10. For example, device 10 may be provided with a full-facedisplay 14 that extends across the entire front face of the device. Ifdesired, display 14 may also wrap around over the edge of the front faceso that at least part of the lateral edges or at least part of the backsurface of device 10 is used for display purposes.

FIG. 2B is a circuit diagram of an illustrative organic light-emittingdiode display pixel 22 in display 14. As shown in FIG. 2B, display pixel22 may include a storage capacitor Cst and associated pixel transistorssuch as a semiconducting-oxide transistor Toxide, a drive transistorTdrive, a data loading transistor Tdata, a first emission transistorTem1, second emission transistor Tem2, and an anode reset transistorTar. While transistor Toxide is formed using semiconducting oxide (e.g.,a transistor with an n-type channel formed from semiconducting oxidesuch as indium gallium zinc oxide or IGZO), the other transistors may bethin-film transistors formed from a semiconductor such as silicon (e.g.,polysilicon channel deposited using a low temperature process, sometimesreferred to as “LTPS” or low-temperature polysilicon).Semiconducting-oxide transistors exhibit relatively lower leakage thansilicon transistors, so implementing transistor Toxide as asemiconducting-oxide transistor will help reduce flicker (e.g., bypreventing current from leaking away from the gate terminal of drivetransistor Tdrive).

In another suitable arrangement, transistors Toxide and Tdrive may beimplemented as semiconducting-oxide transistors while the remainingtransistors Tdata, Tem1, Tem2, and Tar are LTPS transistors. TransistorTdrive serves as the drive transistor and has a threshold voltage thatis critical to the emission current of pixel 22. Since the thresholdvoltage of transistor Tdrive may experience hysteresis, forming thedrive transistor as a top-gate semiconducting-oxide transistor can helpreduce the hysteresis (e.g., a top-gate IGZO transistor experiences lessVth hysteresis than a silicon transistor). If desired, any of theremaining transistors Tdata, Tem1, Tem2, and Tar may be implemented assemiconducting-oxide transistors. In general, any one of transistorsTdrive, Tdata, Tem1, Tem2, and Tar may be either an n-type (i.e.,n-channel) or p-type (i.e., p-channel) silicon thin-film transistor. Ifdesired, pixel 22 may include more or less than six transistors and/ormay include more or less than one internal capacitor.

Display pixel 22 may include an organic light-emitting diode (OLED) 204.A positive power supply voltage VDDEL may be supplied to positive powersupply terminal 200, and a ground power supply voltage VSSEL may besupplied to ground power supply terminal 202. Positive power supplyvoltage VDDEL may be 3 V, 4 V, 5 V, 6 V, 7 V, 2 to 8 V, or any suitablepositive power supply voltage level. Ground power supply voltage VSSELmay be 0 V, −1 V, −2 V, −3 V, −4 V, −5 V, −6V, −7 V, or any suitableground or negative power supply voltage level. The state of drivetransistor Tdrive controls the amount of current flowing from terminal200 to terminal 202 through diode 204, and therefore the amount ofemitted light from display pixel 22. Organic light-emitting diode 204may have an associated parasitic capacitance C_(OLED) (not shown).

Terminal 209 may be used to supply an anode reset voltage Var to assistin turning off diode 204 when diode 204 is not in use. Terminal 209 istherefore sometimes referred to as an anode reset or initializationline. Control signals from display driver circuitry such as row drivercircuitry 34 of FIG. 2A are supplied to control terminals such as rowcontrol terminals 212, 214-1, 214-2, and 214-3. Row control terminal 212may serve as an emission control terminal (sometimes referred to as anemission line or emission control line), whereas row control terminals214-1, 214-2, and 214-3 may serve as first, second, and third scancontrol terminals (sometimes referred to as scan lines or scan controllines). Emission control signal EM may be supplied to terminal 212. Scancontrol signals SC1, SC2, and SC3 may be applied to scan terminals214-1, 214-2, and 214-3, respectively. A data input terminal such asdata signal terminal 210 is coupled to a respective data line D of FIG.2A for receiving image data for display pixel 22. Data terminal 210 mayalso be referred to as a data line.

In the example of FIG. 2B, transistors Tem1, Tdrive, Tem2, and OLED 304may be coupled in series between power supply terminals 200 and 202. Inparticular, first emission control transistor Tem1 may have a sourceterminal that is coupled to positive power supply terminal 200, a gateterminal that receives emission control signal EM2 via emission line212, and a drain terminal (labeled as Node1). The terms “source” and“drain” terminals of a transistor can sometimes be used interchangeablyand may therefore sometimes be referred to as “source-drain” terminals.Drive transistor Tdrive may have a source terminal coupled to Node1, agate terminal (labeled as Node2), and a drain terminal (labeled asNode3). Second emission control transistor Tem2 may have a sourceterminal coupled to Node3, a gate terminal that also receives emissioncontrol signal EM via emission line 212, and a drain terminal (labeledas Node4) coupled to ground power supply terminal 202 via light-emittingdiode 204. Configured in this way, emission control signal EM can beasserted to turn on transistors Tem1 and Tem2 during an emission phaseto allow current to flow through light-emitting diode 204.

Storage capacitor Cst may have a first terminal that is coupled topositive power supply line 200 and a second terminal that is coupled toNode2. Image data that is loaded into pixel 22 can be at least bepartially stored on pixel 22 by using capacitor Cst to hold chargethroughout the emission phase. Transistor Toxide may have a sourceterminal coupled to Node2, a gate terminal configured to receive scancontrol signal SC1 via scan line 214-1, and a drain terminal coupled toNode3. Signal SC1 may be asserted to turn on transistor Toxide to shortthe drain and gate terminals of transistor Tdrive. A transistorconfiguration where the gate and drain terminals are shorted issometimes referred to as being “diode-connected.”

Data loading transistor Tdata may have a source terminal coupled to dataline 210, a gate terminal configured to receive scan control signal SC2via scan line 214-2, and a drain terminal coupled to Node1. Configuredin this way, signal SC2 can be asserted to turn on transistor Tdata,which will allow a data voltage from data line 210 to be loaded ontoNode1. Transistor Tar may have a source terminal coupled to Node4, agate terminal configured to receive scan control signal SC3 via scanline 214-3, and a drain terminal coupled to initialization line 209.Configured in this way, scan control signal SC3 can be asserted to turnon transistor Tar, which drives Node4 to the anode reset voltage levelVar. If desired, the anode reset voltage Var on line 209 can bedynamically biased to different levels during operation of pixel 22.

Device 10 having a full-face display 14 covering the entire front faceof the device may have to mount sensor 13 below display 14. FIG. 3 is across-sectional side view of an illustrative display stack of display 14that at least partially covers a sensor in accordance with anembodiment. As shown in FIG. 3, the display stack may include a backingfilm 300 and a substrate such as substrate 302 formed on backing film300. Substrate 302 may be formed from glass, metal, plastic, ceramic,sapphire, or other suitable substrate materials. In some arrangements,substrate 302 may be an organic substrate formed from polyimide (PI),polyethylene terephthalate (PET), or polyethylene naphthalate (PEN) (asexamples). The surface of substrate 302 may optionally be covered withone or more buffer layers (e.g., inorganic buffer layers such as layersof silicon oxide, silicon nitride, etc.).

Thin-film transistor (TFT) layers 304 may be formed over substrate 302.The TFT layers 304 may include thin-film transistor circuitry such asthin-film transistors, thin-film capacitors, associated routingcircuitry, and other thin-film structures formed within multiple metalrouting layers and dielectric layers. Organic light-emitting diode(OLED) layers 306 may be formed over the TFT layers 304. The OLED layers306 may include a diode cathode layer, a diode anode layer, and emissivematerial interposed between the cathode and anode layers.

Circuitry formed in the TFT layers 304 and the OLED layers 306 may beprotected by encapsulation layers 308. As an example, encapsulationlayers 308 may include a first inorganic encapsulation layer, an organicencapsulation layer formed on the first inorganic encapsulation layer,and a second inorganic encapsulation layer formed on the organicencapsulation layer. Encapsulation layers 308 formed in this way canhelp prevent moisture and other potential contaminants from damaging theconductive circuitry that is covered by layers 308.

One or more polarizer films 312 may be formed over the encapsulationlayers 308 using adhesive 310. Adhesive 310 may be implemented usingoptically clear adhesive (OCA) material that offer high lighttransmittance. One or more touch layers 316 that implement the touchsensor functions of touch-screen display 14 may be formed over polarizerfilms 312 using adhesive 314 (e.g., OCA material). For example, touchlayers 316 may include horizontal touch sensor electrodes and verticaltouch sensor electrodes collectively forming an array of capacitivetouch sensor electrodes. Lastly, the display stack may be topped offwith a coverglass layer 320 that is formed over the touch layers 316using additional adhesive 318 (e.g., OCA material). Cover glass 320 mayserve as an outer protective layer for display 14.

Still referring to FIG. 3, sensor 13 may be formed under the displaystack within the electronic device 10. As described above in connectionwith FIG. 1, sensor 13 may be an optical sensor such as a camera (e.g.,an infrared camera), proximity sensor, ambient light sensor, fingerprintsensor, or other light-based sensor. In such scenarios, the performanceof sensor 13 depends on the transmission of light traversing through thedisplay stack, as indicated by arrow 350. A typical display stack,however, has fairly limited transmission properties. For instance, morethan 80% of light in the visible spectrum might be lost when travelingthrough the display stack, which makes sensing under display 14challenging.

Each of the multitude of layers in the display stack contributes to thedegraded light transmission to sensor 13. In particular, the densethin-film transistors and associated routing structures in TFT layers304 of the display stack contribute substantially to the lowtransmission. In accordance with an embodiment, at least some of thedisplay pixels may be selectively removed in regions of the displaystack located directly over sensor(s) 13. Regions of display 14 that atleast partially cover or overlap with sensor(s) 13 in which at least aportion of the display pixels have been removed are sometimes referredto as “pixel removal regions.” Each pixel removal region may still havepixels, albeit with a lower density of subpixels. Removing displaypixels (e.g., removing transistors and/or capacitors associated with oneor more sub-pixels) in the pixel free regions can drastically helpincrease transmission and improve the performance of the under-displaysensor 13. The pixel removal regions may therefore have a first subpixeldensity, whereas the rest of the display (often referred to collectivelyas the active area) may exhibit a second (“native”) subpixel densitythat is greater than the first subpixel density. The native subpixeldensity of the active area may be at least two times, three times, fourtimes, 1-5 times, or 1-10 times the subpixel density of the pixelremoval regions.

FIGS. 4A-4D are top views showing various pixel removal regions forimproving optical transmission in accordance with some embodiments. Asan example, display 14 may generally include a repeating pixel group 400that includes red (R) subpixels, green (G) subpixels, and blue (B)subpixels. As shown in FIG. 4A, each pixel group 400 may include tworows of colored subpixels, where the top row includes BGRG subpixels inthat order and where the bottom row includes RGBG subpixels in thatorder. This particular pattern is merely illustrative and is notintended to limit the scope of the present embodiments. If desired,other color display patterns may be implemented in display 14, which caninclude subpixels of other colors (e.g., cyan subpixels, magentasubpixels, yellow subpixels, clear subpixels, etc.).

In the example of FIG. 4A, every other pixel group 400 has been removedin accordance with a checkerboard pattern. The stippled regionsillustrate where subpixels would have existed if no removal scheme isimplemented but is now at least partially devoid of thin-film transistorcircuitry corresponding to the display subpixels that have been removed.Each individual stippled region may be referred to as a non-pixelregion, pixel free regions or pixel lacking region. This type of pixelremoval scheme may remove up to 50% of all available display subpixels.

In FIG. 4A, each non-pixel region represents eight removed sub-pixels.FIG. 4B illustrates another pixel removal scheme in which each stipplednon-pixel region represents 12 removed subpixels in anothercheckerboard-like pattern. This type of pixel removal scheme may alsoremove up to 50% of all available display subpixels. FIG. 4C illustratesyet another pixel removal scheme in which some stippled pixel freeregions represent four removed subpixels while other stippled pixel-freeregions represent only two removed subpixels in a repeating mosaic-likepattern. This type of pixel removal scheme may also remove up to 50% ofall available display subpixels. FIG. 4D illustrates yet another pixelremoval scheme in each stippled pixel lacking region represents twelveremoved subpixels while removing more than 50% of all available displaysubpixels from the pixel removal region overall.

In general, the amount of pixel removal in the pixel removal regionshould be carefully chosen so as to maximize optical transmittancethrough the display stack while ensuring that the effective pixels perinch (PPI) is still sufficiently high such that the user of device 10will not be able to visually notice any undesired display artifacts inthe vicinity of the pixel removal region over which sensor(s) 13 may belocated. The exemplary pixel removal regions of FIGS. 4A-4D are merelyillustrative. If desired, other pixel removal arrangements in which upto 10% of display subpixels have been removed in the pixel removalregion, up to 20% of display subpixels have been removed, up to 30% ofdisplay subpixels have been removed, up to 40% of display subpixels havebeen removed, up to 50% of display subpixels have been removed (i.e.,the subpixel density of the pixel removal region may be half of thesubpixel density of the native active area), 0-50% of display subpixelshave been removed, 10-50% of display subpixels have been removed, 20-50%of display subpixels have been removed, 30-50% of display subpixels havebeen removed, 51-90% of display subpixels have been removed, or morethan 50% of display subpixels have been removed (i.e., the subpixeldensity of the pixel removal region may be less than half of thesubpixel density of the native active area) may be implemented toachieve the desired level of optical transmittance through the displaystack.

The illustrative pixel removal schemes shown in the embodiments of FIGS.4A-4D may not be capable of providing a uniform distribution ofsubpixels in all directions across the surface of display 14. To providea uniform distribution of subpixels across the display surface, anintelligent pixel removal process may be implemented that systematicallyeliminates the closest subpixel of the same color (e.g., the nearestneighbor of the same color may be removed). FIG. 5A is a top layout viewshowing how red subpixels can be systematically removed in accordancewith an embodiment. The blue and green subpixels are omitted from FIG.5A to help avoid obscuring the present embodiments.

As shown in FIG. 5A, display 14 may be initially provided with an arrayof red subpixels 22R. The pixel removal process may involve selecting agiven subpixel, identifying the closest or nearest neighboring subpixels(in terms of distance from the selected subpixel), and theneliminating/omitting those identified subpixels in the final pixelremoval region. For instance, subpixel 22R-1 may represent a firstselected subpixel. The two closest subpixels may then be marked forelimination (as indicated by markup “X”). Subpixel 22R-2 may represent asecond selected subpixel. The four closest subpixels (which includes thetwo previously marked subpixels) may be marked for elimination. Thispixel removal process may be performed across the entire display pixelarray for subpixels of all colors.

FIG. 5A illustrates the resulting subpixel array after one iteration ofpixel removal has been performed. If desired, additional iterations ofsubpixel removal may be performed to further increase transmittance atthe expense of lower pixel density. FIG. 5B illustrates the resultingsubpixel array after another iteration of pixel removal has beenperformed (e.g., a second order result by again eliminating the closestneighboring subpixels). If desired, any suitable number of iterationsmay be carried out. Systematically removing subpixels in this way canprovide uniform color balance while maintaining a high PPI.

FIG. 6A shows how subpixels of various colors may be removed using aprocess of the type described in connection with FIG. 5A. As shown inFIG. 6A, each pixel group 600 may include two rows of colored subpixels,where the top row includes RGBG subpixels in that order and where thebottom row includes BGRG subpixels in that order. In particular, thered, green, and first green subpixels may be removed from the first row,whereas only the second green subpixel is removed from the second row ineach pixel group 600. The resulting arrangement of the pixel removalregion implemented using this method is illustrated in FIG. 6B. As shownin FIG. 6B, some of the stippled pixel lacking regions represent threeconsecutive removed subpixels while other pixel lacking regionsrepresent only one removed subpixel. This type of pixel removal schememay also remove 50% of all available display subpixels in the pixelremoval region (e.g., the pixel density of the pixel removal region maybe half of the native pixel density of the active area).

FIG. 6C illustrates another suitable arrangement where additional bluesubpixels are removed from the configuration of FIG. 6A. As shown inFIG. 6C, every other pixel group 600 will have all of the blue subpixelsremoved. In other words, more blue sub-pixels may be removed or omittedrelative to the green or red subpixels (i.e., the density of the bluesubpixels is lower than the density of the red subpixels in the pixelremoval region). This example where the non-uniform subpixelremoval/omission is targeted towards blue subpixels is merelyillustrative and is not intended to limit the present embodiments. Ifdesired, more green subpixels may be omitted relative to the blue/redsubpixels, more red subpixels may be omitted relative to the blue/greensubpixels, or other non-uniform subpixel removal scheme may beimplemented. In yet other suitable embodiments, the degree of omissionof all the different colored subpixels may be different, which willaffect the density of each subpixel. As an example, more blue subpixelsmay be removed than the green subpixels, and more green subpixels may beremoved than the red subpixels (i.e., the blue subpixels have thehighest removal rate and thus the lowest subpixel density, whereas thered subpixels have the lowest removal rate). As another example, moreblue subpixels may be removed than the red subpixels, and more redsubpixels may be removed than the green subpixels (i.e., the bluesubpixels have the highest removal rate, whereas the green subpixelshave the lowest removal rate and thus the highest subpixel density). Asyet another example, more green subpixels may be removed than the bluesubpixels, and more blue subpixels may be removed than the red subpixels(i.e., the green subpixels have the highest omission rate, whereas thered subpixels have the lowest omission rate). Other permutations mayalso be implemented.

The example of FIG. 6B where each individual subpixel is illustrated asa rectangular region have edges parallel to the display edge is merelyillustrative. If desired, each subpixel region may have edges that areangled or rotated relative to the display edge (see, e.g., FIG. 6D). InFIG. 6D, the display edge may be parallel to the X axis or the Y axis.The front face of the display may be parallel to the XY plane such thata user of the device views the front face of the display in the Zdirection. Portion 610 of FIG. 6D shows the native subpixel arrangementprior to removal. Portion 612 illustrates how every other subpixel maybe removed for each color—the removed subpixels are marked using “X”).Portion 614 shows the resulting pixel configuration with 50% of thesubpixels removed.

In the example of FIG. 6D, the subpixels are removed such that there arehorizontal stripes of empty pixel regions (see, e.g., continuousstriping regions 615 devoid of subpixels in portion 614). This is merelyillustrative. If desired, the subpixels may also be removed to createvertical stripes of empty pixel regions (see, e.g., FIG. 6E havingcontiguous striping regions 617 devoid of subpixels).

As described above in connection with FIG. 5B, multiple iterations ofpixel removal may be performed. FIG. 6F is a diagram of a pixelarrangement after two pixel removal iterations. Compared to theconfiguration in portion 614 of FIG. 6D, the configuration of FIG. 6Fhas an even smaller subpixel density (e.g., by again eliminating theclosest neighboring subpixels, the second order result may have onlyhalf the number of subpixels compared to the first order result). Inother words, after two pixel removal iterations, 75% of the originalnative subpixels may be removed. If desired, any suitable number ofiterations may be implemented. Systematically removing subpixels in thisway can provide uniform color balance while maintaining a high PPI.

As described above in connection with FIG. 6C, non-uniform subpixelomission may be implemented. FIG. 6G is a diagram of a pixel arrangementwhere more green subpixels have been removed (e.g., a second round ofremoval may be performed only for the green subpixels). Compared to theconfiguration in portion 614 of FIG. 6D, the configuration of FIG. 6Ghas the same number of blue and red subpixels but has only half thenumber of green subpixels remaining. Since the native pixel group hastwo green subpixels for every red and blue subpixel pair, eliminatingthe nearest green neighbors twice may help balance the total number ofgreen, red, and blue subpixels (e.g., the total number of remaining red,green, and blue subpixels may be the same). In other words, the densityof the blue subpixels is equal to the density of the blue subpixels andis equal to the density of the red subpixels in the pixel removalregion. If desired, the remaining green subpixels may optionally beenlarged in size to help compensate for the reduction in number.

The native RGBG/BGRG subpixel arrangement illustrated in portion 610 ofFIG. 6D may sometimes be referred to as having a “pentile” arrangement.If desired, the illustrative pixel removal schemes described herein mayalso be applied to non-pentile or straight pixel arrangements. FIG. 6His a diagram of a non-pentile pixel arrangement after pixel removal. Asshown in FIG. 6H, the number of remaining blue, red, and green subpixelsare the same, but the blue region subpixel regions may be larger in sizethan the green subpixel regions, and the green subpixel regions may belarger in size than the red subpixel regions. This is merelyillustrative. In general, the size of the different colored subpixelregions may be tuned for optimal display performance.

In general, the display subpixels may be partially removed from anyregion(s) of display 14. FIGS. 7A-7F are front views showing how display14 may have one or more localized regions in which the pixels areselectively removed using the scheme of FIGS. 4-6 in accordance withcertain embodiments. The example of FIG. 7A illustrates various localpixel removal regions 700 physically separated from one another (i.e.,the various pixel removal regions 700 are non-continuous). The term“active area” may refer to regions of display 14 outside of andnon-overlapping with the pixel removal regions. The various local areas700 might for example correspond to three different sensors formedunderneath display 14. The example of FIG. 7B illustrates a continuouspixel removal region 702 formed along the top border of display 14,which might be suitable when there are many optical sensors positionednear the top edge of device 10. The example of FIG. 7C illustrates apixel removal region 704 formed at a corner of display 14. In somearrangements, the corner of display 14 in which pixel removal region 704is located may be a rounded corner or a corner having a substantially90° corner. The example of FIG. 7D illustrates a pixel removal region706 formed only in the center portion along the top edge of device 10(i.e., the pixel removal region covers a recessed notch area in thedisplay). FIG. 7E illustrates another example in which pixel removalregions 708 and 710 can have different shapes and sizes. FIG. 7Fillustrates yet another suitable example in which the pixel removalregion covers the entire display surface. These examples are merelyillustrative and are not intended to limit the scope of the presentembodiments. If desired, any one or more portions of the displayoverlapping with optically based sensors or other sub-display electricalcomponents may be designated as a pixel removal region/area.

In yet another suitable arrangement, a pixel removal region may beformed at a curved edge portion of the display. FIG. 7G is across-sectional side view of display 14 showing a curved or bentperipheral edge region 20. A user 750 may view the front face of display14 by looking in the direction of arrow 752 that is parallel to the Zdirection. The front face of display 14 is parallel to the XY plane. Asshown in FIG. 7G, a pixel removal region 714 may be formed in the bentedge portion 20. In general, one or more edges of the device may becurved or bent, and one or more pixel removal regions may optionally beformed in each curved edge portion.

FIG. 8A is a top layout view showing how some subpixels may beselectively removed from a pixel group 600 to increase transmittance inaccordance with the pixel removal scheme shown in FIGS. 6A and 6B. Theregions labeled “sub-pixel removed” correspond to pixel free regionsthat are completely devoid of thin-film transistors and capacitors thatwould otherwise be present had those subpixels not been removed.Removing the thin-film transistor structures, which might include activesilicon or other semiconducting material, associated source-draincontacts, and also thin-film capacitor terminals, can help improveoptical transmittance through the display stack in the pixel freeregions.

As shown in FIG. 8A, the red, green, and blue subpixels have beenremoved from the upper portion of pixel group 600, whereas only therightmost green subpixel has been removed from the lower portion ofpixel group 600. FIG. 8A also shows various gate (G) lines (e.g.,horizontal or row control lines) and data (D) lines (e.g., vertical orcolumn control lines) that are routed over the thin-film transistorsassociated each display subpixel. Moreover, power supply lines carryingpower supply voltages ELVDD might also be routed in the verticalcolumn-wise direction. If desired, the power supply lines may also oralternatively be routed in the horizontal direction or in a diagonalfashion across the surface of the display.

If desired, the pixel structure of FIG. 8A may optionally be rotated orangled relative to a display edge that is parallel to the X axis or theY axis. As an example, the pixel arrangement of FIG. 8A may be rotatedat a 45° angle relative to the X axis. If desired, the pixel structuresmay be rotated by other suitable angles (e.g., by 30°, by 60°, by 90°,by 1-89°, etc.).

In the example of FIG. 8A, the power supply lines (see, e.g., the widervertical routing traces) are still routed over the non-pixel regions,which contributes to the reduction in overall optical transmittance. Inaccordance with another suitable arrangement illustrated in FIG. 8B, thepower supply lines may be selectively removed or omitted from the pixelfree regions such as regions 850 and 851 (e.g., from each region wheresubpixels should be removed). As shown in FIG. 8B, the wider ELVDDrouting traces are absent and no longer routed through non-pixel regions850 and 851. Even though the ELVDD routing lines are shown as beingbroken into various segments in the vertical direction, the differentpower segments are still connected together using a conductive powermesh 810 formed in a higher routing layer than the ELVDD routing lines.Interconnecting the separate power line segments using power mesh 810allows all of the remaining subpixels to be properly supplied withpower. Selectively eliminating the power supply routing traces from thenon-pixel areas can help further improve transmittance in the overallpixel removal region. In the example of FIG. 8B, there are stillhorizontal gate lines and vertical data lines that are routed overnon-pixel regions 850 and 851, which may contribute to diffraction forlight traveling through these regions. In certain embodiments, theseconductive traces may be rerouted to provide a larger continuous openingin the non-pixel regions (see, e.g., FIG. 8C). As shown in FIG. 8C, gatelines G′ and data lines D′ may be routed in a more circuitous manner toachieve a larger open area. Routing the control signals in this wayreduces diffraction albeit at the expense of decreased transmission.

In both FIGS. 8A and 8B, the diamond-shaped regions correspond to theOLEDs of each colored subpixel. In FIG. 8B, the thin-film transistorsassociated with the blue, green, and red subpixels may be formed inregion 856 overlapping with the corresponding OLEDs, whereas thethin-film transistors associated with the green subpixel to the rightmay be formed in region 858. Since TFT regions 856 and 858 are notcontinuous with one another, the non-pixel regions 850 and 851 are alsonon-continuous with each other.

FIG. 8D illustrates another suitable arrangement in which the thin-filmtransistors associated with the lone green subpixel (i.e., the upperright green subpixel in pixel group 600) is shifted or relocated intoregion 851 such that the pixel group 600 can have a continuous pixelfree region 860. The OLED of the green subpixel may remain unchanged. Inother words, all the TFT structures are formed in row region 862,whereas row region 860 may be substantially devoid of TFT structures tohelp attain a larger continuous opening for improved transmittance.

The amount of current flowing through the drive transistor (e.g.,transistor Tdrive in FIG. 2B) may be relatively high for remainingsubpixels within a pixel removal region. To help mitigate potentiallyaging effects associated with the high drive current levels, the size ofthe remaining subpixels may be enlarged (e.g., the OLED and/or some ofthe associated transistors may be increased in size). In the example ofFIG. 8E, the OLEDs of remaining blue subpixel B′, green subpixels G′,and red subpixel R′ may be relatively larger than the OLEDs in otherparts of the display with native subpixel density (i.e., relative todisplay pixels in the normal active area). Enlarging the OLEDs reducescurrent density, which can help prolong the lifetime of the diodes. Ifenlarging the pixel transistors, transistors such as the drivetransistor may have its width increased and/or gate length decreased tohelp mitigate any potential accelerated aging effects due to the highdrive current levels.

FIG. 8F illustrates another suitable arrangement showing how an opaquemask such as mask 870 may be used to define an aperture opening. Mask870 may be formed using existing metal routing layers, a pixeldefinition layer (e.g., a black pixel defining layer), and/or othersuitable opaque layer. As shown in FIG. 8F, opaque mask 870 may haveopenings such as opening 872 aligned with a corresponding pixel freeregion (i.e., a continuous region where subpixels have been removedbelow). In general, opening 872 may have a predetermined shape (e.g., arectangular window, a circular window, an oval window, an ellipticalwindow, etc.) configured to help control the diffraction pattern forlight traversing through the opening.

In additional to the thin-film transistor structures, touch basedcircuitry such as touch-sensor traces within the touch layers 316 (FIG.3) might also contribute substantially to the low transmission throughthe display stack. FIG. 9A is a top layout view showing illustrativetouch conductive mesh circuitry 900 formed over the pixel removal regionin accordance with an embodiment. As shown in FIG. 9A, none of the touchmesh 900 is removed (i.e., touch mesh 900 completely overlaps with thepixel removal region), so there is no reduction in touch functionality.On the other extreme, all of touch mesh 900 may be removed from theentire pixel removal region (i.e., the touch mesh and the pixel removalregion are non-overlapping), which offers the highest opticaltransmission while sacrificing the loss of touch functionality in thepixel removal region. Completely removing mesh 900 might, however,result in a noticeable difference in contrast between the pixel removalregion and the surrounding normal display region. For instance, thepixel removal region where touch mesh 900 is completely eliminated mightappear more reflective than the surrounding regions, which may or maynot be acceptable.

FIG. 9B is a top layout view showing how touch conductive mesh circuitry900′ may be partially removed over the pixel removal region inaccordance with another suitable arrangement. As shown in FIG. 9B, touchmesh 900′ may be present over actual display subpixels but may be absentover the pixel free regions where the subpixels have been intelligentlyremoved. This partial removal of the touch circuitry in the pixelremoval region can provide improved optical transmittance while offeringpartial touch functionality and reduced contrast between the pixelremoval region and the surrounding areas.

FIG. 10A is a top layout view showing how the pixel free region such asregion 1000 where subpixel transistor structures have been removed lacksdummy contacts in accordance with an embodiment. A complete lack ofdummy contacts in region 1000 helps maximize optical transmittance sincethe presence of dummy contacts can still block some amount of light. Inaccordance with another suitable arrangement, non-pixel region 1000might actually include some dummy contacts even though the underlyingtransistor(s) have been removed. While the presence of dummy contactsslightly reduces transmittance, including dummy contacts (which may beformed from polysilicon material) helps to provide better polysiliconuniformity during manufacturing.

Polysilicon uniformity may affect the transistor current profile, whichis illustrated in FIG. 10C. FIG. 10C is a plot of emission current (I)versus gate-to-source voltage (Vgs). Curve 1002 may represent thecurrent profile for active p-channel transistors adjacent to region 1000in FIG. 10A, whereas curve 1004 may represent the current profile foractive p-channel transistors adjacent to region 1000 in FIG. 10B. Curve1004 offers a more ideal current behavior while curve 1002 offers ashifted version of the ideal profile. Thus, including dummy contacts inthe pixel free regions can help maintain transistor current uniformityacross the display.

FIG. 11 is a cross-sectional side view of an illustrative display stackshowing how at least some of the blanket layers within the display stackcan be selectively patterned to further improve optical transmittance.FIG. 11 is similar to the cross-section of FIG. 3, but expands upon theTFT layers 304. For example, FIG. 11 shows how TFT layers 304 mayinclude a TFT gate dielectric layer 1100, inorganic passivation layers1102 formed over the TFT gate dielectric layer 1100, one or more organicplanarization layers 1104 formed over inorganic passivation layers 1102,and organic pixel definition layers 1106 formed over organicplanarization layers 1104. Moreover, a protection layer such assubstrate inorganic protection film 303 may be formed between substrate302 and TFT layers 304. In certain embodiments, at least layers 303,1100, 1102, and/or 1106 (which are typically blanket layers that coverthe entire display surface) may be selectively patterned or thinned inthe pixel removal region to further improve optical transmittance. Ifdesired, other blanket display layers may also be selectivelypatterned/thinned to help increase the transmittance of light throughthe display stack.

In accordance with an embodiment, an electronic device is provided thatincludes a display having pixels formed in an active area and a sensorunder the display, the display includes a pixel removal region that atleast partially overlaps with the sensor, the active area has a firstpixel density, and the pixel removal region has a second pixel densitythat is less than the first pixel density.

In accordance with another embodiment, the pixel removal region includesa plurality of pixel free regions each of which is devoid of thin-filmtransistors, and the plurality of pixel free regions is configured toincrease signal transmittance through the display to the sensor.

In accordance with another embodiment, each of the plurality of pixelfree regions is further devoid of power supply lines.

In accordance with another embodiment, horizontal and vertical controllines in the plurality of pixel free regions are rerouted to providecontinuous open areas that reduce the amount of diffraction for lighttraveling through the display to the sensor.

In accordance with another embodiment, each of the plurality of pixelfree regions include rows of continuous open areas within the pixelremoval region.

In accordance with another embodiment, the electronic device includes anopaque mask with openings aligned to the plurality of pixel freeregions.

In accordance with another embodiment, the second pixel density is halfof the first pixel density.

In accordance with another embodiment, the second pixel density is lessthan half of the first pixel density.

In accordance with another embodiment, the display includes anadditional pixel removal region that is physically separated from thepixel removal region.

In accordance with another embodiment, the additional pixel removalregion has a different size than the pixel removal region.

In accordance with another embodiment, the pixel removal region overlapsan entire edge of the display.

In accordance with another embodiment, the pixel removal region overlapsa corner of the display.

In accordance with another embodiment, the pixel removal region overlapsa curved edge of the display.

In accordance with another embodiment, the pixel removal region overlapsa recessed notch area in the display.

In accordance with another embodiment, the pixel removal region overlapsthe entire surface of the display.

In accordance with another embodiment, the pixel removal region includesfirst subpixels of a first color and second subpixels of a second color,and the density of the first subpixels is different than the density ofthe second subpixels in the pixel removal region.

In accordance with another embodiment, the pixel removal region includesblue subpixels and red subpixels, and the density of the blue subpixelsis lower than the density of the red subpixels in the pixel removalregion.

In accordance with another embodiment, the pixel removal region includesgreen subpixels, blue subpixels, and red subpixels, and the density ofthe blue subpixels is equal to the density of the blue subpixels and isequal to the density of the red subpixels in the pixel removal region.

In accordance with another embodiment, the pixels in the active areaincludes first subpixels, and the pixel removal region includes secondsubpixel having larger diodes than the first subpixels of the activearea to mitigate aging.

In accordance with another embodiment, the electronic device includes aconductive touch sensor mesh formed over the display, the conductivetouch sensor overlaps with the pixel removal region.

In accordance with another embodiment, the electronic device includes aconductive touch sensor mesh formed over the display, the conductivetouch sensor mesh does not overlap with the pixel removal region.

In accordance with another embodiment, the pixel removal region includesa plurality of pixel free regions each of which lacks dummy contacts.

In accordance with another embodiment, the pixel removal region includesa plurality of pixel free regions each of which includes dummy contactsconfigured to provide emission current uniformity in the pixel removalregion.

In accordance with another embodiment, the display includes a blanketlayer that is selectively patterned in the pixel removal region toincrease the transmittance of light through the display to the sensor,and the blanket layer is a display layer selected from the groupconsisting of: a substrate protection layer, a gate dielectric layer, aninorganic passivation layer, and an organic pixel definition layer.

In accordance with an embodiment, a display is provided that includespixels formed in an active area and pixels formed in a given regionwithin the active area, the pixels in the active area are formed at afirst pixel density, and the pixels in the given region are formed at asecond pixel density that is less than the first pixel density toincrease the transmittance of light through the given region.

In accordance with an embodiment, an apparatus is provided that includesa display stack having a plurality of blanket display layers and anoptical sensor at least partially covered by the display stack, at leastsome of the blanket display layers are patterned to increase lighttransmittance through the display stack to the optical sensor.

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

1. An electronic device, comprising: a display having pixels formed inan active area; and a sensor under the display, wherein the displaycomprises a pixel removal region that at least partially overlaps withthe sensor, wherein the active area has a first pixel density, andwherein the pixel removal region has a second pixel density that is lessthan the first pixel density.
 2. The electronic device of claim 1,wherein the pixel removal region comprises a plurality of pixel freeregions each of which is devoid of thin-film transistors, and whereinthe plurality of pixel free regions is configured to increase signaltransmittance through the display to the sensor.
 3. The electronicdevice of claim 2, wherein each of the plurality of pixel free regionsis further devoid of power supply lines.
 4. The electronic device ofclaim 2, wherein horizontal and vertical control lines in the pluralityof pixel free regions are rerouted to provide continuous open areas thatreduce the amount of diffraction for light traveling through the displayto the sensor.
 5. The electronic device of claim 2, wherein each of theplurality of pixel free regions comprise rows of continuous open areaswithin the pixel removal region.
 6. The electronic device of claim 2,further comprising: an opaque mask with openings aligned to theplurality of pixel free regions.
 7. The electronic device of claim 1,wherein the second pixel density is half of the first pixel density. 8.The electronic device of claim 1, wherein the second pixel density isless than half of the first pixel density.
 9. The electronic device ofclaim 1, wherein the display comprises an additional pixel removalregion that is physically separated from the pixel removal region. 10.The electronic device of claim 5, wherein the additional pixel removalregion has a different size than the pixel removal region.
 11. Theelectronic device of claim 1, wherein the pixel removal region overlapsan entire edge of the display.
 12. The electronic device of claim 1,wherein the pixel removal region overlaps a corner of the display. 13.The electronic device of claim 1, wherein the pixel removal regionoverlaps a curved edge of the display.
 14. The electronic device ofclaim 1, wherein the pixel removal region overlaps a recessed notch areain the display.
 15. The electronic device of claim 1, wherein the pixelremoval region overlaps the entire surface of the display.
 16. Theelectronic device of claim 1, wherein the pixel removal region comprisesfirst subpixels of a first color and second subpixels of a second color,and wherein the density of the first subpixels is different than thedensity of the second subpixels in the pixel removal region.
 17. Theelectronic device of claim 1, wherein the pixel removal region comprisesblue subpixels and red subpixels, and wherein the density of the bluesubpixels is lower than the density of the red subpixels in the pixelremoval region.
 18. The electronic device of claim 1, wherein the pixelremoval region comprises green subpixels, blue subpixels, and redsubpixels, and wherein the density of the blue subpixels is equal to thedensity of the blue subpixels and is equal to the density of the redsubpixels in the pixel removal region.
 19. The electronic device ofclaim 1, wherein the pixels in the active area comprises firstsubpixels, and wherein the pixel removal region comprises secondsubpixels having larger diodes than the first subpixels of the activearea.
 20. The electronic device of claim 1, further comprising: aconductive touch sensor mesh formed over the display, wherein theconductive touch sensor overlaps with the pixel removal region.
 21. Theelectronic device of claim 1, further comprising: a conductive touchsensor mesh formed over the display, wherein the conductive touch sensormesh does not overlap with the pixel removal region.
 22. The electronicdevice of claim 1, wherein the pixel removal region comprises aplurality of pixel free regions each of which lacks dummy contacts. 23.The electronic device of claim 1, wherein the pixel removal regioncomprises a plurality of pixel free regions each of which includes dummycontacts configured to provide emission current uniformity in the pixelremoval region.
 24. The electronic device of claim 1, wherein thedisplay comprises a blanket layer that is selectively patterned in thepixel removal region to increase the transmittance of light through thedisplay to the sensor, and wherein the blanket layer is a display layerselected from the group consisting of: a substrate protection layer, agate dielectric layer, an inorganic passivation layer, and an organicpixel definition layer.
 25. A display, comprising: pixels formed in anactive area; and pixels formed in a given region within the active area,wherein the pixels in the active area are formed at a first pixeldensity, and wherein the pixels in the given region are formed at asecond pixel density that is less than the first pixel density toincrease the transmittance of light through the given region. 26.Apparatus, comprising: a display stack having a plurality of blanketdisplay layers; and an optical sensor at least partially covered by thedisplay stack, wherein at least some of the blanket display layers arepatterned to increase light transmittance through the display stack tothe optical sensor.
 27. The electronic device of claim 19, wherein thesecond subpixels in the pixel removal region comprises blue subpixels ofa first size and green subpixels of a second size that is smaller thanthe first size.
 28. The electronic device of claim 1, wherein the pixelremoval region comprises green subpixels of a first density and bluesubpixels of a second density that is equal to the first density. 29.The electronic device of claim 1, wherein the display comprises ablanket layer that is selectively patterned in the pixel removal regionto increase the transmittance of light through the display to thesensor, and wherein the blanket layer comprises a cathode layer.